An infinitely long, charged, thin-walled cylinder has a radius, R, of 3.0 cm. The charge per unit length is 5.40 10-9 C/m on the shell.
a) What is the magnitude of the electric Field at radial distance r= (R/2.1) cm from central axis?
b) What is the magnitude of the electric field at radial distance r=(R*2.1) cm from the central axis?